Background: Chronic pain is a common and distressing symptom reported by patients with chronic kidney disease (CKD). Clinical practice and research in this area do not appear to be advancing sufficiently to address the issue of chronic pain management in patients with CKD. Objectives: To determine the prevalence and severity of chronic pain in patients with CKD. Design: Systematic review and meta-analysis. Setting: Interventional and observational studies presenting data from 2000 or later. Exclusion criteria included acute kidney injury or studies that limited the study population to a specific cause, symptom, and/or comorbidity. Patients: Adults with glomerular filtration rate (GFR) category 3 to 5 CKD including dialysis patients and those managed conservatively without dialysis. Measurements: Data extracted included title, first author, design, country, year of data collection, publication year, mean age, stage of CKD, prevalence of pain, and severity of pain. Methods: Databases searched included MEDLINE, CINAHL, EMBASE, and Cochrane Library, last searched on February 3, 2020. Two reviewers independently screened all titles and abstracts, assessed potentially relevant articles, and extracted data. We estimated pooled prevalence of overall chronic pain, musculoskeletal pain, bone/joint pain, muscle pain/soreness, and neuropathic pain and the I2 statistic was computed to measure heterogeneity. Random effects models were used to account for variations in study design and sample populations and a double arcsine transformation was used in the model calculations to account for potential overweighting of studies reporting either very high or very low prevalence measurements. Pain severity scores were calibrated to a score out of 10, to compare across studies. Weighted mean severity scores and 95% confidence intervals were reported. Results: Sixty-eight studies representing 16 558 patients from 26 countries were included. The mean prevalence of chronic pain in hemodialysis patients was 60.5%, and the mean prevalence of moderate or severe pain was 43.6%. Although limited, pain prevalence data for peritoneal dialysis patients (35.9%), those managed conservatively without dialysis (59.8%), those following withdrawal of dialysis (39.2%), and patients with earlier GFR category of CKD (61.2%) suggest similarly high prevalence rates. Limitations: Studies lacked a consistent approach to defining the chronicity and nature of pain. There was also variability in the measures used to determine pain severity, limiting the ability to compare findings across populations. Furthermore, most studies reported mean severity scores for the entire cohort, rather than reporting the prevalence (numerator and denominator) for each of the pain severity categories (mild, moderate, and severe). Mean severity scores for a population do not allow for “responder analyses” nor allow for an understanding of clinically relevant pain. Conclusions: Chronic pain is common and often severe across diverse CKD populations providing a strong imperative to establish chronic pain management as a clinical and research priority. Future research needs to move toward a better understanding of the determinants of chronic pain and to evaluating the effectiveness of pain management strategies with particular attention to the patient outcomes such as overall symptom burden, physical function, and quality of life. The current variability in the outcome measures used to assess pain limits the ability to pool data or make comparisons among studies, which will hinder future evaluations of the efficacy and effectiveness of treatments. Recommendations for measuring and reporting pain in future CKD studies are provided. Trial registration: PROSPERO Registration number CRD42020166965
Chronic Pain Severity in Opioid-Dependent Patients
